As messaging terminals in selective call communication systems become more sophisticated, the management of messages and the messaging terminals, to handle a variety of types of messages and responses in a flexible and non-intrusive manner is becoming important for customer satisfaction. For example, a messaging terminal for use with a messaging system may consist of a telephone handset and a digital messaging device which share a common telephone line. The telephone is used to generate a voice or DTMF selective call message while the digital messaging device is used to generate a digital selective call message, which are often stored for queued delivery. The originator of such a message may expect a response in digital form, or by a voice telephone call from the responding party. Additionally, unsolicited voice messages may be received at the messaging terminal in the form of voice telephone calls. The user of the messaging terminal may prefer, and expect, to receive responses to messages in digital form, as would be necessary when the response is a sophisticated alphanumeric message which cannot be easily synthesized by a computer in the messaging system. When the messaging terminal is a digital only device, without a telephone handset, the response would be needed in digital form. 0n the other hand, the user may have both a handset and a digital messaging device and the user may prefer and expect a voice response, either "real time", or stored.
A known means of delivering voice and data messages to a messaging terminal which may be receiving it at a handset or by a digital device, which has been used successfully, is to use a signal unique to data transfer protocols at the beginning part of a response call. An example is a modem connect signal, used by modems to establish a call setup in accordance with standard protocols. When the messaging terminal answers a response telephone call, the messaging terminal responds with a modem connect signal, after which the messaging system controller can then complete the setup and perform a data transfer of the response. In systems using this feature to identify the message type, the user who expects a voice message can be annoyed by hearing data signals upon answering a call with the handset, or by having to wait while the messaging terminal determines whether a modem is at the other end of the telephone call before connecting the handset to the telephone call.
Another message management issue in more sophisticated messaging systems is the need to route responses to a message to a phone number other than the phone number used to originate the message. This flexibility is becoming more important as customers become more familiar with messaging systems at the same time as messaging systems are becoming larger in scope--leading to higher probability of response delays. Longer response delays lead to the situation where the message originator will be at another phone number when the response is expected to be received. A similar situation arises when the originator receives a response but immediately forwards it to another phone number for handling by a third party.
Thus, what is needed is a method and apparatus to efficiently deliver responses to designated messaging terminals, completing the delivery of a data or voice response in the manner preferred by the user of the messaging terminal which receives the response, and without delivering intrusive data signals to the user's handset during the delivery of the response call.